1. Field of the Invention
This invention relates to the manufacture of tampons and has to do more particularly with the formation of tubular overwraps or tampon sacks and the filling of such sacks with an absorptive aggregate as an incident of their formation.
2. Description of the Prior Art
This invention is concerned with the manufacture of tampons of the type disclosed in commonly owned U.S. Pat. No. 3,815,601, dated June 11, 1974 and entitled "Catamenial Aggregate Absorbent Body". In accordance with the teachings of the said patent, the tampon comprises an aggregate composed of individual pieces of absorbent, foam-like material encased within a flexible, fluid-permeable overwrap in the nature of a tubular sack closed at its opposite ends, the ends of the sack being gathered inwardly and secured to form end closures or seals. A withdrawal string is attached to one end of the sack and the sack is inverted to form it into rosette shape, the end of the sack opposite the withdrawal string being displaced inwardly to form a cavity in the overwrap, thereby forming a tampon structure in which the absorbent aggregate is encased by an overwrap having an exterior portion forming the exterior surface of the tampon and a re-entrant portion forming the surface of the cavity. Subsequent to the formation of the tampon into rosette shape, it is radially compressed and enclosed in a tube-type inserter from which the tampon may be ejected in its intended position of use.
The present invention has to do with procedures for forming and filling the tubular sacks in a high speed, continuous operation to provide a continious series of filled sacks which are in condition to be transferred to succeeding processing apparatus for the completion of the sack forming operations. In particular, the present invention contemplates the provision of apparatus for metering the aggregate into discrete charges and loading the charges into the tubed sack-forming material as an incident of the formation of the completed sacks.
In part the present invention may utilize the tube forming techniques taught in commonly owned U.S. Application Ser. No. 484,813, filed July 1, 1974 and entitled "Apparatus And Method For Continuously Forming And Filling Tampon Sacks". In accordance with the teachings of this application, a continuous web of sack-forming material is printed with adhesive at spaced apart intervals at which end closures for the sacks are to be formed, the adhesive dried, and the web tubed around a hollow mandrel with the longitudinal edges of the web overlapped and sealed to form the longitudinal seam of the tubing. The present invention embodies similar tube forming techniques to the extent that a web of tube forming material will be preprinted with adhesive, the adhesive dried, and the web tubed and seamed about a hollow mandrel. However, in accordance with the said application, the hollow mandrel about which the tubing is formed is provided adjacent its trailing end with a funnel-like hopper into which measured increments of absorbent aggregate are sequentially deposited from a source of supply, as by means of a series of continuously moving measuring cups having diplaceable bottoms adapted to open as the cups pass over the hopper. As each charge of aggregate is deposited in the hopper, the charge is subjected to a blast of air which acts to propel the material through the mandrel and into the tubed web. In distinction to the foregoing, the present invention contemplates the provision of a loading gun having a rotary loading wheel which accurately meters and delivers charges of aggregate to the mandrel in a continuous high speed operation.
The aforesaid application also teaches the provision of a rotating turret having a plurality of pleating and sealing stations which sequentially engage and gather the tubing and seal it together in the areas of the previously applied adhesive to form a continuous series of sacks. As the leading end closure of each successive sack is formed, a charge of aggregate introduced into the tubing through the mandrel is propelled through the tubing so that the charge comes to rest against the leading end closure of the sack being formed, whereupon the formation of the next successive end closure completes the sack and encloses the deposited charge of material. In contrast, the present invention contemplates the provision of apparatus coacting with the aforementioned loading gun to align and position the charges of aggregate in the tubing at predetermined intervals corresponding to the length of the sacks being formed and transfer the filled tubing to additional mechanism for sealing the sacks.
While its utility is not so limited, the present invention is specifically intended for use in conjunction with the apparatus and procedures taught in commonly owned U.S. Application Ser. No. 517,110, filed Oct. 22, 1974, and entitled "Loop Knot Tying Method And Apparatus". In accordance with the invention taught in the last named application, a rotating drum is provided carrying about its periphery a plurality of identical operating heads equally spaced from each other. A continuous tube of flexible overwrap material having measured increments of aggregate or filling material within the tube at predetermined spaced apart intervals is engaged by the heads as the drum rotates. Each head is provided with operating components which first pleats a segment of the tubing at an intended end closure and clamps it in pleated condition, one of the clamps engaging the tubing at the position of a glue stripe, whereupon the clamp is heated to activate the adhesive and seal the tube. A string metering device, in cooperation with a string tensioner, meters an appropriate length of string to a needle and the needle engages the string and perforates the tubing carrying the string through the perforation. A spreader-pliers thereafter passes within the string loop formed by the needle and to either side of the needle so as to engage the free ends of the string, the string having been previously cut by a string clamp and shear assembly. The needle is then retracted and the spreader-pliers draw the free ends of the string through the loop to form a simple loop knot, whereupon the tubing is severed and the individual sack so-formed is suspended by its string from the spreader-pliers and displaced for pick-up by a transfer means which conveys the tampon sack to additional apparatus for subsequent processing. The present invention constitutes the means for forming and supplying the filled tubing to the apparatus just described.
Reference is also made to commonly owned application Ser. No. 531,222 filed Dec. 10, 1974, and entitled "Apparatus And Method For Forming Tampons And Assembling Same In Inserters", which teaches apparatus and procedures for receiving the completed tampon sacks formed by the heads on the aforementioned rotating drum, the sacks being transferred by their strings to a rotary turret having a multiplicity of assembling stations mounted about is periphery, the assembly stations each being provided with means for forming a tampon sack into rosette shape, compacting it, and inserting it into a tube-type inserter.
As should now be evident, the present invention comprises a part of an integrated system for the manufacture of tampons, commencing with the basic raw materials which are fabricated and assembled into a finished product in a high speed, continuous series of operations.